Aioli à la greque is a very thick vinaigrette sauce served with fish that has fried or boiled.
The sauce is made with fresh breadcrumbs that have been sieved and soaked in milk, ground nuts (a mixture of walnuts, almonds and hazelnuts), and crushed garlic. To this mixture, oil, vinegar and lemon juice are added.
Sources
New Larousse Gastronomique. Paris: Librairie Larousse. English edition 1977. Page 6.